24.. In order to cultivate the power of attention, bring a photograph with you to the same seat in the same room in the same position as heretofore. Examine it closely at least ten minutes, note the expression of the eyes, the form of the features, the clothing, the way the hair is arranged; in fact, note every detail shown on the photograph carefully. Now cover it and close your eyes and try to see it mentally; if you can see every detail perfectly and can form a good mental image of the photograph, you are to be congratulated; if not, repeat the process until you can.

So in this exercise while examining the photo does it matter if your mind wanders? Is the purpose to pay attention to the detail of the photo and make the clear mental image? I just wanna be sure I'm doing it correctly.